A two-phase and two-dimensional mathematical model of heat transfer within tubular flow apparatus packed with a bed of pellets has been proposed, in which radial distributions of the bed voidage and of the fluid velocity over the cross-section of the apparatus are considered. The thermokinetic parameters of the model have been evaluated according to the information available in literature, as well as to our own experience, and the model has been verified by comparison of the temperature radial profiles computed with those experimentally determined at the same conditions. A satisfactory agreement has been observed for a certain set of the values of the model parameters. The parametric sensitivity of the model has been also studied and limits have been determined in which the variations of the values of the individual parameters of the model are permissible without any risk of making significant error in simulation of the temperature profiles.